Index: lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -8824,10 +8824,24 @@
                    None); // This is not an ABI copy.
   SDValue Chain = DAG.getEntryNode();
 
-  ISD::NodeType ExtendType = (FuncInfo.PreferredExtendType.find(V) ==
-                              FuncInfo.PreferredExtendType.end())
-                                 ? ISD::ANY_EXTEND
-                                 : FuncInfo.PreferredExtendType[V];
+  ISD::NodeType ExtendType = ISD::ANY_EXTEND;
+  if (V->getType()->isIntegerTy(1)) {
+    // Respect getBooleanContents while extending i1 values
+    switch (TLI.getBooleanContents(/*isVec=*/false, /*isFloat=*/false)) {
+    case TargetLowering::ZeroOrOneBooleanContent:
+      ExtendType = ISD::ZERO_EXTEND;
+      break;
+    case TargetLowering::ZeroOrNegativeOneBooleanContent:
+      ExtendType = ISD::SIGN_EXTEND;
+      break;
+    case TargetLowering::UndefinedBooleanContent:
+      break;
+    }
+  } else if (FuncInfo.PreferredExtendType.find(V) !=
+             FuncInfo.PreferredExtendType.end()) {
+    ExtendType = FuncInfo.PreferredExtendType[V];
+  }
+
   RFV.getCopyToRegs(Op, DAG, getCurSDLoc(), Chain, nullptr, V, ExtendType);
   PendingExports.push_back(Chain);
 }
Index: test/CodeGen/WebAssembly/bug-40172.ll
===================================================================
--- /dev/null
+++ test/CodeGen/WebAssembly/bug-40172.ll
@@ -0,0 +1,47 @@
+; RUN: llc < %s -O0 -debug 2>&1 | FileCheck %s
+
+; Regression test for bug 40172. The problem was that when FastISel
+; fell back to DAG ISel for the code below, the DAG was combined down
+; to a fragment that looked like
+;
+;   t2: i32,ch = CopyFromReg t0, Register:i32 %0
+;     t24: i1 = truncate t2
+;        t8: i32 = any_extend t24
+;          t10: ch = CopyToReg t0, Register:i32 %6, t8
+;
+; Where the icmp yielding %x5 has been combined away into the
+; truncate-extend pair. However, in the next step the truncate-extend
+; pair is combined out, yielding
+;
+;   t2: i32,ch = CopyFromReg t0, Register:i32 %0
+;     t10: ch = CopyToReg t0, Register:i32 %6, t2
+;
+; Which no longer produces a bool that respects
+; getBooleanContents. The extend should have been a zero_extend to
+; start out with so that getBooleanContents would be respected.
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
+; CHECK:      t0: ch = EntryToken
+; CHECK-NEXT:   t2: i32,ch = CopyFromReg t0, Register:i32 %0
+; CHECK-NEXT:     t3: i8 = truncate t2
+; CHECK-NEXT:       t5: i8 = and t3, Constant:i8<1>
+; CHECK-NEXT:         t7: i1 = setcc t5, Constant:i8<1>, seteq:ch
+; CHECK-NEXT:           t8: i32 = zero_extend t7
+; CHECK-NEXT:             t10: ch = CopyToReg t0, Register:i32 %5, t8
+
+define void @test(i8 %byte) {
+  %t = alloca { i8, i8 }, align 1
+  %x4 = and i8 %byte, 1
+  %x5 = icmp eq i8 %x4, 1
+  %x6 = and i8 %byte, 2
+  %x7 = icmp eq i8 %x6, 2
+  %x8 = bitcast { i8, i8 }* %t to i8*
+  %x9 = zext i1 %x5 to i8
+  store i8 %x9, i8* %x8, align 1
+  %x10 = getelementptr inbounds { i8, i8 }, { i8, i8 }* %t, i32 0, i32 1
+  %x11 = zext i1 %x7 to i8
+  store i8 %x11, i8* %x10, align 1
+  ret void
+}
Index: test/CodeGen/X86/and-sink.ll
===================================================================
--- test/CodeGen/X86/and-sink.ll
+++ test/CodeGen/X86/and-sink.ll
@@ -52,12 +52,13 @@
 ; CHECK-NEXT:    je .LBB1_5
 ; CHECK-NEXT:  # %bb.1: # %bb0.preheader
 ; CHECK-NEXT:    movb {{[0-9]+}}(%esp), %al
+; CHECK-NEXT:    andb $1, %al
 ; CHECK-NEXT:    movl {{[0-9]+}}(%esp), %ecx
 ; CHECK-NEXT:    .p2align 4, 0x90
 ; CHECK-NEXT:  .LBB1_2: # %bb0
 ; CHECK-NEXT:    # =>This Inner Loop Header: Depth=1
 ; CHECK-NEXT:    movl $0, B
-; CHECK-NEXT:    testb $1, %al
+; CHECK-NEXT:    testb %al, %al
 ; CHECK-NEXT:    je .LBB1_5
 ; CHECK-NEXT:  # %bb.3: # %bb1
 ; CHECK-NEXT:    # in Loop: Header=BB1_2 Depth=1
Index: test/CodeGen/X86/fast-isel-select.ll
===================================================================
--- test/CodeGen/X86/fast-isel-select.ll
+++ test/CodeGen/X86/fast-isel-select.ll
@@ -10,9 +10,12 @@
 ; CHECK-LABEL: fastisel_select:
 ; CHECK:       ## %bb.0:
 ; CHECK-NEXT:    movb %sil, %al
+; CHECK-NEXT:    andb $1, %al
 ; CHECK-NEXT:    movb %dil, %cl
+; CHECK-NEXT:    andb $1, %cl
 ; CHECK-NEXT:    xorl %esi, %esi
 ; CHECK-NEXT:    subb %al, %cl
+; CHECK-NEXT:    andb $1, %cl
 ; CHECK-NEXT:    testb $1, %cl
 ; CHECK-NEXT:    movl $1204476887, %edi ## imm = 0x47CADBD7
 ; CHECK-NEXT:    cmovnel %edi, %esi
Index: test/CodeGen/X86/gpr-to-mask.ll
===================================================================
--- test/CodeGen/X86/gpr-to-mask.ll
+++ test/CodeGen/X86/gpr-to-mask.ll
@@ -107,6 +107,7 @@
 ; X86-64-NEXT:  # %bb.1: # %if
 ; X86-64-NEXT:    movb (%rdx), %al
 ; X86-64-NEXT:    addb (%rcx), %al
+; X86-64-NEXT:    andb $1, %al
 ; X86-64-NEXT:    jmp .LBB2_3
 ; X86-64-NEXT:  .LBB2_2: # %else
 ; X86-64-NEXT:    movb (%rcx), %al
@@ -120,19 +121,20 @@
 ; X86-32:       # %bb.0: # %entry
 ; X86-32-NEXT:    vmovss {{.*#+}} xmm0 = mem[0],zero,zero,zero
 ; X86-32-NEXT:    vmovss {{.*#+}} xmm1 = mem[0],zero,zero,zero
-; X86-32-NEXT:    movl {{[0-9]+}}(%esp), %ecx
+; X86-32-NEXT:    movl {{[0-9]+}}(%esp), %edx
 ; X86-32-NEXT:    movl {{[0-9]+}}(%esp), %eax
 ; X86-32-NEXT:    testb $1, {{[0-9]+}}(%esp)
 ; X86-32-NEXT:    je .LBB2_2
 ; X86-32-NEXT:  # %bb.1: # %if
-; X86-32-NEXT:    movl {{[0-9]+}}(%esp), %edx
-; X86-32-NEXT:    movb (%edx), %dl
-; X86-32-NEXT:    addb (%ecx), %dl
+; X86-32-NEXT:    movl {{[0-9]+}}(%esp), %ecx
+; X86-32-NEXT:    movb (%ecx), %cl
+; X86-32-NEXT:    addb (%edx), %cl
+; X86-32-NEXT:    andb $1, %cl
 ; X86-32-NEXT:    jmp .LBB2_3
 ; X86-32-NEXT:  .LBB2_2: # %else
-; X86-32-NEXT:    movb (%ecx), %dl
+; X86-32-NEXT:    movb (%edx), %cl
 ; X86-32-NEXT:  .LBB2_3: # %exit
-; X86-32-NEXT:    kmovd %edx, %k1
+; X86-32-NEXT:    kmovd %ecx, %k1
 ; X86-32-NEXT:    vmovss %xmm1, %xmm0, %xmm0 {%k1}
 ; X86-32-NEXT:    vmovss %xmm0, (%eax)
 ; X86-32-NEXT:    retl
@@ -213,11 +215,10 @@
 ; X86-64-NEXT:    je .LBB4_2
 ; X86-64-NEXT:  # %bb.1: # %if
 ; X86-64-NEXT:    movb (%rsi), %al
-; X86-64-NEXT:    jmp .LBB4_3
+; X86-64-NEXT:    movb %al, (%rcx)
+; X86-64-NEXT:    retq
 ; X86-64-NEXT:  .LBB4_2: # %else
 ; X86-64-NEXT:    movb (%rdx), %al
-; X86-64-NEXT:  .LBB4_3: # %exit
-; X86-64-NEXT:    andb $1, %al
 ; X86-64-NEXT:    movb %al, (%rcx)
 ; X86-64-NEXT:    retq
 ;
@@ -233,7 +234,6 @@
 ; X86-32-NEXT:    movl {{[0-9]+}}(%esp), %ecx
 ; X86-32-NEXT:  .LBB4_3: # %exit
 ; X86-32-NEXT:    movb (%ecx), %cl
-; X86-32-NEXT:    andb $1, %cl
 ; X86-32-NEXT:    movb %cl, (%eax)
 ; X86-32-NEXT:    retl
 entry:
Index: test/CodeGen/X86/test-shrink-bug.ll
===================================================================
--- test/CodeGen/X86/test-shrink-bug.ll
+++ test/CodeGen/X86/test-shrink-bug.ll
@@ -76,7 +76,7 @@
 ; CHECK-X64-NEXT:    pshufd {{.*#+}} xmm1 = xmm0[1,0,3,2]
 ; CHECK-X64-NEXT:    pand %xmm0, %xmm1
 ; CHECK-X64-NEXT:    pextrw $4, %xmm1, %eax
-; CHECK-X64-NEXT:    testb $1, %al
+; CHECK-X64-NEXT:    andb $1, %al
 ; CHECK-X64-NEXT:    jne .LBB1_2
 ; CHECK-X64-NEXT:  # %bb.3: # %no
 ; CHECK-X64-NEXT:    callq bar
Index: test/CodeGen/X86/xmulo.ll
===================================================================
--- test/CodeGen/X86/xmulo.ll
+++ test/CodeGen/X86/xmulo.ll
@@ -711,6 +711,7 @@
 ; FAST-LABEL: bug27873:
 ; FAST:       ## %bb.0:
 ; FAST-NEXT:    movq %rdi, %rax
+; FAST-NEXT:    andb $1, %sil
 ; FAST-NEXT:    movl $160, %ecx
 ; FAST-NEXT:    mulq %rcx
 ; FAST-NEXT:    seto %al